Validation and accountability are vital in most scientific industries and especially so in the pharmaceutical and biotechnological industries. A major challenge to these industries is the need to demonstrate accurately and reproducibly that sterility is achieved and maintained throughout production lines within a plant. This must be done in a manner which meets the stringent requirements of regulatory bodies such as the United States FDA. Acceptable standards can be difficult to be met when a substance is transferred from one sterile location to another sterile location by non direct means.
One current practice includes providing a holding vessel into which substance can be transferred by means of a connecting valve. The holding vessel is transferred to the second sterile location and the substance is then transferred from the holding vessel into the second sterile location via one or more connecting valves. The connecting valves and holding vessel can be sterilised using conventional techniques such as gas, radiation or steam sterilisation. However during connection of the connecting valve to the first sterile location, the external connecting surface of the connecting valve is exposed to the atmosphere and sterility of the valve is compromised.
Alternative methods of substance transfer suffer from similar problems.
For example, in the use of an autoclavable port, where a non-sterile male port is attached to an empty non-sterile bulk vessel prior to sterilization, the entire assembled apparatus is then sterilised by autoclaving. However, a major disadvantage of this technique is that the vessel must be empty before sterilisation.
Alternatively, an irradiated port can be used, where a non-sterile male port is attached to an empty non-sterile disposable bag prior to sterilisation of the whole by irradiation. Again a major disadvantage associated with this system is that the bag must be empty before sterilisation.
A further method of substance transfer involves connecting a transfer port to a vessel under aseptic conditions. With this method it is irrelevant whether or not the vessel is empty or filled. However despite the necessity to undertake these actions in a designated ‘Grade A’ zone, there is an increased risk of contamination due to the making and breaking of various connections. The mere fact that a ‘Grade A’ zone is required to complete these actions requires a significant financial investment by a company wishing to employ this technique.
Another technique incorporates the use of a tube fuser. A sterile bulk vessel is attached to tubing emanating from a sterile port through a tube fuser. This technique is undesirable for numerous reasons including the restricted choice of tubing. This in turn limits the types of substance that can be transferred through the tubing. It is also undesirable to use wetted tubing. Furthermore there is also a potential risk of cross-contamination and re-contamination.
Despite the numerous attempts to find a sterile method of substance transfer none have been wholly successful. In all of the above techniques the sterility of the port or valve used to transfer the substance from one vessel to another is compromised during the connection process or is susceptible to contamination. This is undesirable and leads to problems when validating a product.
Piston-operated valves for the above applications are known. These act by moving a piston up and down or sliding over and back within an apertured housing so as to cover or uncover the fluid communication apertures of the housing. O-ring seals are provided for sealing between the open and closed valve positions. Such valves therefore have slots for receiving the O-rings and the difficulties of assuring that these slots and the spaces about them are not subject to contamination render them questionable for use in sterile transfer systems.
WO 03/090842 discloses a valve including a piston moveable within a housing. The opening of the valve including a sealing plug member connected to the piston so that as the piston is withdrawn away from the opening, it pulls the plug with it, causing the plug to rupture about a weakening formed in its rim and to tear away from the opening thereby breaking the seal.
It is an object of the present invention to seek to alleviate the aforementioned problems.